Martyr Limited Clearance Shaft Anode with Allen Screw – Zinc | Saltwater (CMC12)
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Martyr Limited Clearance Shaft Anode with Allen Screw – Zinc | Saltwater (CMC12)
The Martyr CMC12 is a zinc limited clearance shaft anode designed for propeller shaft installations where a standard cylindrical anode cannot fit due to tight clearances near the hull, strut, or cutlass bearing. The low-profile design provides effective galvanic corrosion protection on the shaft while fitting in spaces where conventional shaft anodes would contact surrounding structure. A stainless steel Allen head screw is included for secure installation.
Zinc is the standard anode material for saltwater use, providing reliable galvanic protection in the higher conductivity of marine water. Martyr Anodes are manufactured to OEM-quality specifications.
Key Features
- Limited clearance low-profile design — fits where standard cylindrical shaft anodes cannot
- Zinc construction — correct material for saltwater use
- Stainless steel Allen head screw included for secure installation
- Protects the propeller shaft from galvanic corrosion
- OEM-quality Martyr Anodes construction
Compatible Applications
- Propeller shafts in saltwater environments with limited clearance to hull, strut, or cutlass bearing
- Inboard and shaft-drive vessels where standard shaft anodes will not fit
- Saltwater and marine environments
Parts Desk Insights
The CMC12 limited clearance shaft anode is the right choice for inboard vessel owners who operate in saltwater and have tight clearances around the propeller shaft that prevent the use of a standard cylindrical anode. This is a common situation on vessels where the shaft runs close to the hull, a strut, or the cutlass bearing housing. The low-profile design sacrifices some anode mass compared to a full cylindrical anode, so replacement intervals may be shorter — inspect the anode regularly and replace when it has depleted to approximately half its original size. If you operate in freshwater, a magnesium anode would be required instead. For the Seachoice streamlined shaft anodes (a different low-drag design for freshwater), see the Seachoice Streamlined Shaft Anode – 2” (Model X9), Magnesium, 1½” (Model X7), and 1¼” (Model X5).
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 1-3 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
Returns & Satisfaction Guarantee
We stand firmly behind the quality of every product we sell. Your confidence matters to us — and we back it with a straightforward 30-Day Satisfaction Guarantee.
If you are not fully satisfied, you may request a return within 30 days of delivery. All returns must receive pre-approval prior to being sent back. Unauthorized returns will not be accepted.
To qualify for a return:
Item must be in new, unused condition
Product must be in its original packaging
All parts, components, hardware, manuals, and accessories must be included
Packaging must be undamaged and suitable for resale
Important:
Electronics are strictly inspected. No returns on open-box electronics. Exceptions may apply only with prior written approval. Any electronic unit that has been installed, powered, activated, or altered may not be eligible for return.
We are serious about product integrity — and equally serious about taking care of our customers. If there is ever a product issue, contact us immediately so we can make it right.
For return authorization, please contact our support team before shipping anything back.